Accumulated Other Comprehensive Income (Loss) (Schedule Of After-Tax Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Selling, general and administrative	$ 22,012	$ 21,829
Beginning of Period	(179,987)	(176,669)
Other comprehensive income (loss) before reclassifications	(1,801)	1,774
Amounts reclassified from accumulated other comprehensive income (loss)	2,737	2,459
Net other comprehensive income (loss) - current period	936	4,233
End of Period	(179,051)	(172,436)
Income before income taxes	23,811	23,451
Income Tax Expense (Benefit)	4,026	5,287
Net income	19,785	18,164
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period	(96,940)	(86,178)
Other comprehensive income (loss) before reclassifications	(790)	1,906
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss) - current period	(790)	1,906
End of Period	(97,730)	(84,272)
Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period	(1,601)	459
Other comprehensive income (loss) before reclassifications	(1,011)	(132)
Amounts reclassified from accumulated other comprehensive income (loss)	658	(153)
Net other comprehensive income (loss) - current period	(353)	(285)
End of Period	(1,954)	174
Pension & Other Post-retirement Benefit Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period	(81,446)	(90,950)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	2,079	2,612
Net other comprehensive income (loss) - current period	2,079	2,612
End of Period	(79,367)	(88,338)
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	(793)	206
Income Tax Expense (Benefit)	(135)	53
Net income	(658)	153
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Pension & Other Post-retirement Benefit Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income Tax Expense (Benefit)	(592)	(762)
Net income	(2,079)	(2,612)
Amortization Of Prior Service Costs And Net Gains Loss	(2,671)	(3,374)
Aluminum Futures Contracts [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Freight	(617)	232
Selling, General and Administrative Expenses [Member] \| Foreign Currency Forward Contracts [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Selling, general and administrative	(191)
Freight		(41)
Cost of Sales [Member] \| Foreign Currency Forward Contracts [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Freight	$ 15	$ 15

Amortization Of Prior Service Costs And Net Gains Loss

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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